Is diplomacy now the only way to get rid of Gaddafi?

After four months of NATO military operations, Libya's Brother Leader, Colonel Gaddafi, is still in power in Tripoli. The rebels still show no sign of overpowering him, nor are the coalition able to step up their efforts under the current UN Security Council resolution. So what is the best way to break the deadlock? Given the pressure on coalition leaders to resolve the conflict, it seems negotiations may be the only remaining path.